The Kel-Tec RFB if they ever launch the "sniper" version with 32" barrel. I'll be getting one when/if they do
There are some accurate non restricted rifles but they are generally just modified oldstyle hunting rifles like the FN-AR-398 (note: not an AR rifle).
https://shopquestar.com/shopping65/shopexd.asp?id=1249&bc=no
People have modified M14 rifles to be fairly accurate. However the M110 and the Armalite rifles along with a number of the other AR10 family rifles are generally .5 moa rifles. That FN hunting rifle dressed in black and trying to look like a black rifle is supposed to be very accurate. I just personally really hate the looks of it.
There are a few others in the wings. Such as the XCR-Mythical in .308. Also a Swiss Arms .308 version is supposed to be around some day.